Question

A student was asked to multiply a number by \(\frac{3}{2}\) but he divided that number by \(\frac{3}{2}\). His result was 10 less than the correct answer. The number was:
1. 20
2. 15
3. 12
4. 10

Answer 1

Correct Answer - Option 3 : 12

Given:

Multiply by a number = 3/2.

But he divide the number = 3/2.

Concept used:

Using linear equation.

Calculation:

Let the number be 'x'.

Number when multiply by 3/2 = (3x)/2

Number when divide by 3/2 = x/(3/2) = (2x)/3

According to the question,

((3x)/2) – ((2x)/3) = 10

⇒ (9x – 4x)/6 = 10

⇒ 5x = 60

⇒ x = 12

∴ The number was 12.